2012-01-12 06:28:30 +08:00
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//===-- RegAllocBase.cpp - Register Allocator Base Class ------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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2014-02-23 03:31:28 +08:00
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// This file defines the RegAllocBase class which provides common functionality
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2012-01-12 06:28:30 +08:00
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// for LiveIntervalUnion-based register allocators.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "regalloc"
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#include "RegAllocBase.h"
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#include "Spiller.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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2012-04-03 06:44:18 +08:00
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#include "llvm/CodeGen/LiveRangeEdit.h"
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2012-11-29 03:13:06 +08:00
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#include "llvm/CodeGen/LiveRegMatrix.h"
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2012-01-12 06:28:30 +08:00
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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2012-11-29 03:13:06 +08:00
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#include "llvm/CodeGen/VirtRegMap.h"
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2012-01-12 06:28:30 +08:00
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#ifndef NDEBUG
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#include "llvm/ADT/SparseBitVector.h"
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#endif
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/Timer.h"
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using namespace llvm;
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STATISTIC(NumNewQueued , "Number of new live ranges queued");
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// Temporary verification option until we can put verification inside
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// MachineVerifier.
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static cl::opt<bool, true>
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VerifyRegAlloc("verify-regalloc", cl::location(RegAllocBase::VerifyEnabled),
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cl::desc("Verify during register allocation"));
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2013-07-17 11:11:32 +08:00
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const char RegAllocBase::TimerGroupName[] = "Register Allocation";
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2012-01-12 06:28:30 +08:00
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bool RegAllocBase::VerifyEnabled = false;
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//===----------------------------------------------------------------------===//
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// RegAllocBase Implementation
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//===----------------------------------------------------------------------===//
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2013-11-19 08:57:56 +08:00
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// Pin the vtable to this file.
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void RegAllocBase::anchor() {}
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2012-06-21 06:52:29 +08:00
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void RegAllocBase::init(VirtRegMap &vrm,
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LiveIntervals &lis,
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LiveRegMatrix &mat) {
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2012-01-12 06:28:30 +08:00
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TRI = &vrm.getTargetRegInfo();
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MRI = &vrm.getRegInfo();
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VRM = &vrm;
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LIS = &lis;
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2012-06-21 06:52:29 +08:00
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Matrix = &mat;
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2012-11-28 08:21:29 +08:00
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MRI->freezeReservedRegs(vrm.getMachineFunction());
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2012-01-12 06:28:30 +08:00
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RegClassInfo.runOnMachineFunction(vrm.getMachineFunction());
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}
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// Visit all the live registers. If they are already assigned to a physical
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// register, unify them with the corresponding LiveIntervalUnion, otherwise push
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// them on the priority queue for later assignment.
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void RegAllocBase::seedLiveRegs() {
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NamedRegionTimer T("Seed Live Regs", TimerGroupName, TimePassesIsEnabled);
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2012-06-21 05:25:05 +08:00
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for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
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unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
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if (MRI->reg_nodbg_empty(Reg))
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continue;
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enqueue(&LIS->getInterval(Reg));
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2012-01-12 06:28:30 +08:00
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}
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}
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// Top-level driver to manage the queue of unassigned VirtRegs and call the
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// selectOrSplit implementation.
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void RegAllocBase::allocatePhysRegs() {
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seedLiveRegs();
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// Continue assigning vregs one at a time to available physical registers.
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while (LiveInterval *VirtReg = dequeue()) {
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assert(!VRM->hasPhys(VirtReg->reg) && "Register already assigned");
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// Unused registers can appear when the spiller coalesces snippets.
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if (MRI->reg_nodbg_empty(VirtReg->reg)) {
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DEBUG(dbgs() << "Dropping unused " << *VirtReg << '\n');
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LIS->removeInterval(VirtReg->reg);
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continue;
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}
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// Invalidate all interference queries, live ranges could have changed.
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2012-06-21 06:52:29 +08:00
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Matrix->invalidateVirtRegs();
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2012-01-12 06:28:30 +08:00
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// selectOrSplit requests the allocator to return an available physical
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// register if possible and populate a list of new live intervals that
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// result from splitting.
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DEBUG(dbgs() << "\nselectOrSplit "
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2013-11-23 03:07:42 +08:00
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<< MRI->getRegClass(VirtReg->reg)->getName()
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<< ':' << *VirtReg << " w=" << VirtReg->weight << '\n');
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2013-08-15 07:50:04 +08:00
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typedef SmallVector<unsigned, 4> VirtRegVec;
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2012-01-12 06:28:30 +08:00
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VirtRegVec SplitVRegs;
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unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs);
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if (AvailablePhysReg == ~0u) {
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// selectOrSplit failed to find a register!
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// Probably caused by an inline asm.
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2014-03-13 14:02:25 +08:00
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MachineInstr *MI = 0;
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for (MachineRegisterInfo::reg_instr_iterator
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I = MRI->reg_instr_begin(VirtReg->reg), E = MRI->reg_instr_end();
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I != E; ) {
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MachineInstr *TmpMI = &*(I++);
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if (TmpMI->isInlineAsm()) {
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MI = TmpMI;
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2012-01-12 06:28:30 +08:00
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break;
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2014-03-13 14:02:25 +08:00
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}
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}
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2012-01-12 06:28:30 +08:00
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if (MI)
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2013-10-06 03:33:37 +08:00
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MI->emitError("inline assembly requires more registers than available");
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2012-01-12 06:28:30 +08:00
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else
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2013-10-06 03:33:37 +08:00
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report_fatal_error("ran out of registers during register allocation");
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2012-01-12 06:28:30 +08:00
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// Keep going after reporting the error.
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VRM->assignVirt2Phys(VirtReg->reg,
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RegClassInfo.getOrder(MRI->getRegClass(VirtReg->reg)).front());
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continue;
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}
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if (AvailablePhysReg)
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2012-06-21 06:52:29 +08:00
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Matrix->assign(*VirtReg, AvailablePhysReg);
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2012-01-12 06:28:30 +08:00
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for (VirtRegVec::iterator I = SplitVRegs.begin(), E = SplitVRegs.end();
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I != E; ++I) {
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2013-08-15 07:50:04 +08:00
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LiveInterval *SplitVirtReg = &LIS->getInterval(*I);
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2012-01-12 06:28:30 +08:00
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assert(!VRM->hasPhys(SplitVirtReg->reg) && "Register already assigned");
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if (MRI->reg_nodbg_empty(SplitVirtReg->reg)) {
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DEBUG(dbgs() << "not queueing unused " << *SplitVirtReg << '\n');
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LIS->removeInterval(SplitVirtReg->reg);
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continue;
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}
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DEBUG(dbgs() << "queuing new interval: " << *SplitVirtReg << "\n");
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assert(TargetRegisterInfo::isVirtualRegister(SplitVirtReg->reg) &&
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"expect split value in virtual register");
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enqueue(SplitVirtReg);
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++NumNewQueued;
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}
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}
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}
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